The invention relates to a mixing valve for liquids, particularly for sanitary purposes, with a spherical plug and having communicating inlets and outlets, a valve housing having a valve face adapted to the spherical plug and into which issue a discharge pipe and two intake pipes for the liquids to be mixed which can be connected to at least two openings of the spherical plug, and an operating rod connected to the spherical plug and guided in a recess of said plug by means of which the plug is pivotable for varying the quantity of the outflowing liquid and is rotatable for varying the mixing ratio of the inflowing liquids, the inlets and outlets of the spherical plug being arranged in each case homologously to a plane of symmetry passing through the operating rod axis and at right angles to the pivot axis.
Such mixing valves are popular, particularly due to their convenient and easy operation. This is not only due to the fact that they can be operated by one hand, but particularly due to the fact that, without changing the set mixing ratio of the inflowing liquids (e.g. hot and cold water), they can be closed by simply pressing down the operating rod or the knob, grip or handle rigidly connected thereto and can be opened by simply raising the operating rod or the knob, grip or handle rigidly connected thereto. This is advantageous not only in cases where a rapid opening or closing of the valve is desired, but also particularly in those cases where a contamination of the operating rod or its grip (e.g. by dirty hands) or a contamination of the hands by the operating rod or its grip (e.g. in medical practices) is to be avoided.
If mixing valves of this type are to be used for mixing hot and cold water, e.g. as wash basin fittings, they must always be fitted in such a way that the clockwise turning of the operating rod or a clockwise pivoting or rotation of the grip rigidly connected thereto leads to a reduction in the temperature of the outflowing water and a counterclockwise turning of the operating rod or a counterclockwise pivoting or rotation of the grip rigidly connected thereto brings about an increase in the temperature of the outflowing water. However, in the hitherto known mixing valves of the type described hereinbefore, this is only possible if the hot and cold water supply pipes run in a convenient manner, i.e. out of sight of the wash basin user with the cold water pipe to the right and the hot water pipe to the left, because otherwise and without undesired and costly supply pipe crossovers, which are often not possible due to the limited space available, the turning of the operating rod or a pivoting or rotation of the grip rigidly connected thereto in a clockwise direction leads to an increase and not to a decrease of the temperature of the outflowing water.
This problem is particularly serious, e.g. in cases where it is a question of fitting in space-saving manner identical wash basins equipped with identical mixing valves on either side of a wall with connection to a hot and cold water supply pipe arranged in vertically juxtaposed manner within said wall, because out of sight of the wash basin user the hot water supply pipe is to the right of the cold water supply pipe on one side of said wall and to the left thereof on the other side of said wall.